Abstarct: In this thesis, morphology, structural and sensing properties of titanium dioxide nanostructures prepared by different methods such as chemical oxidation‚ Chemical vapor deposition(CVD) and spray Pyrolysis were studied. Titanium foil substrate have been for CVD and chemical oxidation methods but for the 3rd method p-type Si (100) has been used. Several samples with chemical oxidation method using ethylene glycol electrolyte solution with ammonium fluoride (as acid) at a concentration of 10% water electrolyte solution were prepared. For these samples the voltage of 60V were choosen and samples were anneled at 500℃. FESEM image reveals the formation of titanium dioxide nanotube. XRD spectra show grows of anatase phase with preferential growth along the (101) shows. Gas response properties of nanotubes for acetone vapor, ethanol, water and ammonia was studied at different temperatures and concentrations, According to the results, working temperature were 200℃, 300℃, 300℃ and 250℃‚ respectively. Nanoplate TiO2 were synthesized using chemichal vapor deposition.The source temperature was choose around 850℃ to get the best samples. FESEM images show the formation of titanium dioxide nano plate. XRD spectra indicate the formation of tetragonal Rutıle phase with the preferred direction (110). Acetone vapor sensing properties of the samples were analyzed at the working temperature of 250℃. Also titanium dioxide nanoparticles prepared by spray pyrolysıs. XRD patterns indicate the formation of anatase crystalline phase with a preferential direction (101). Gas response of samples toward aceton vapor was studied at the working temperature of 300℃.